Ok three weeks since is happened to my car, it's done around two hundred miles now and still smoking from the exhaust ! A mixture of black/ greyish looking muck. I keep an eye on the oil level and it's not budged so it's not burning engine oil off. At first I thought it was improving but I think his was partly wishful thinking. Intercooler looks ok , oil clean etc ,no over heating or strange noises either. I figured it may be an air leak or be over fueling but wouldn't this show up on diagnostics?? I'm seriously loosing the love for this car as it appears to be turning into a large money pit. The car didn't lose much oil so it can't be still burning it off...another thought is could the cat be fubarred?? Any ideas before I sell the thing as a smoker and lose thousands?